Drive control circuit for dental treatment instruments

A drive control circuit for controlling driving of dental treatment instruments by means of driving devices associated therewith, operating data for which is adapted to be fed into a forward/backward counter when a particular treatment instrument is selected for usage, comprising:

• a. a forward/backward counter, having a counting pulse input, and being adapted to be fed with operating data;
• b. a starter switch coupled to said forward/backward counter and being operable, when actuated, to change the count of the forward/backward counter step-wise, for transmission to a control element, which is associated with the particular dental treatment instrument;
• and
• c. control circuit means coupled between said forward/backward counter and said starter switch and being operable, upon actuation of the starter switch, to change the count in said forward/backward counter at a variable rate by increasing the counting speed of the forward/backward counter with increasing actuation time of the starter switch by increasing the variable rate at which counting pulses are produced at the counting pulse input of said forward/backward counter.